.. contents::
:local:
- :depth: 1
.. toctree::
:hidden:
This document describes extensions to tools and formats LLVM seeks compatibility
with.
+General Assembly Syntax
+===========================
+
+C99-style Hexadecimal Floating-point Constants
+----------------------------------------------
+
+LLVM's assemblers allow floating-point constants to be written in C99's
+hexadecimal format instead of decimal if desired.
+
+.. code-block:: gas
+
+ .section .data
+ .float 0x1c2.2ap3
+
Machine-specific Assembly Syntax
================================
X86/COFF-Dependent
------------------
-The following additional relocation type is supported:
+Relocations
+^^^^^^^^^^^
+
+The following additional relocation types are supported:
**@IMGREL** (AT&T syntax only) generates an image-relative relocation that
corresponds to the COFF relocation types ``IMAGE_REL_I386_DIR32NB`` (32-bit) or
.long fun@IMGREL
.long (fun@imgrel + 0x3F)
.long $unwind$fun@imgrel
+
+**.secrel32** generates a relocation that corresponds to the COFF relocation
+types ``IMAGE_REL_I386_SECREL`` (32-bit) or ``IMAGE_REL_AMD64_SECREL`` (64-bit).
+
+**.secidx** relocation generates an index of the section that contains
+the target. It corresponds to the COFF relocation types
+``IMAGE_REL_I386_SECTION`` (32-bit) or ``IMAGE_REL_AMD64_SECTION`` (64-bit).
+
+.. code-block:: gas
+
+ .section .debug$S,"rn"
+ .long 4
+ .long 242
+ .long 40
+ .secrel32 _function_name
+ .secidx _function_name
+ ...
+
+``.linkonce`` Directive
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Syntax:
+
+ ``.linkonce [ comdat type [ section identifier ] ]``
+
+Supported COMDAT types:
+
+``discard``
+ Discards duplicate sections with the same COMDAT symbol. This is the default
+ if no type is specified.
+
+``one_only``
+ If the symbol is defined multiple times, the linker issues an error.
+
+``same_size``
+ Duplicates are discarded, but the linker issues an error if any have
+ different sizes.
+
+``same_contents``
+ Duplicates are discarded, but the linker issues an error if any duplicates
+ do not have exactly the same content.
+
+``associative``
+ Links the section if a certain other COMDAT section is linked. This other
+ section is indicated by its section identifier following the comdat type.
+ The following restrictions apply to the associated section:
+
+ 1. It must be the name of a section already defined.
+ 2. It must differ from the current section.
+ 3. It must be a COMDAT section.
+ 4. It cannot be another associative COMDAT section.
+
+``largest``
+ Links the largest section from among the duplicates.
+
+``newest``
+ Links the newest section from among the duplicates.
+
+
+.. code-block:: gas
+
+ .section .text$foo
+ .linkonce
+ ...
+
+ .section .xdata$foo
+ .linkonce associative .text$foo
+ ...
+
+``.section`` Directive
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+MC supports passing the information in ``.linkonce`` at the end of
+``.section``. For example, these two codes are equivalent
+
+.. code-block:: gas
+
+ .section secName, "dr", discard, "Symbol1"
+ .globl Symbol1
+ Symbol1:
+ .long 1
+
+.. code-block:: gas
+
+ .section secName, "dr"
+ .linkonce discard
+ .globl Symbol1
+ Symbol1:
+ .long 1
+
+Note that in the combined form the COMDAT symbol is explicit. This
+extension exits to support multiple sections with the same name in
+different comdats:
+
+
+.. code-block:: gas
+
+ .section secName, "dr", discard, "Symbol1"
+ .globl Symbol1
+ Symbol1:
+ .long 1
+
+ .section secName, "dr", discard, "Symbol2"
+ .globl Symbol2
+ Symbol2:
+ .long 1